Create small watchdog service for filter settings

[nefarius]

Windows updates and/or upgrades like to nuke the registry settings required for the filter driver to load properly, giving the user the impression HH silently stopped working. This can typically be solved with a reinstall but all that's really necessary are two things:

• Is the driver binary and service still there?
• Are the UpperFilters entries still there?

If not, a watchdog could automatically correct this e.g. on boot.